Dyonic Masses from Conformal Field Strengths in D even Dimensions

Abstract

We show that D/2--form gauge fields in D even dimensions can get a mass with both electric and magnetic contributions when coupled to conformal field--strengths whose gauge potentials is are \frac {D-2}{2}- forms. Denoting by e^I_Łand m^{IŁ} the electric and magnetic couplings, gauge invariance requires: e^I_Łm^{JŁ}\mp e^J_Łm^{IŁ}=0, where I,Ł= 1... m denote the species of gauge potentials of degree D/2 and gauge fields of degree D/2-1, respectively. The minus and plus signs refer to the two different cases D=4n and D=4n+2 respectively and the given constraints are respectively {\rm {Sp}}(2m) and {\rm {O}}(m,m) invariant. For the simplest examples, (I,Ł=1 for D=4n and I,Ł=1,2 for D=4n+2) both the e,m quantum numbers contribute to the mass \m=\sqrt {e^2 +m^2} . This phenomenon generalizes to $D$ even dimensions the coupling of massive antisymmetric tensors which appear in D=4 supergravity Lagrangians which derive from flux compactifications in higher dimensions. For D=4 we give the supersymmetric generalization of such couplings using N=1 superspace.

11 pages, LaTeX source, typos corrected. Version to appear on Phys.Lett.B